1. Field of the Invention
The present invention relates to an automotive air conditioner which can control airflow of both heated and cooled air by sliding a mixing door inside of a case.
2. Description of Prior Art
In order to clarify the task of the present invention, some conventional automotive air conditioners will be briefly described before describing the detail of the present invention.
One of the conventional air conditioners is of a type which comprises an intake unit through which outside/inside air is taken in, a cooler unit with an evaporator through which the air is cooled and a heater unit with a heater core through which the air is heated. As is known, the evaporator is a device set in a refrigerant circulation cooling system, through which a low temperature-low pressure refrigerant from an expansion valve flows for cooling air passing therethrough, and the heater core is a device through which a warmed engine cooling water from an operating engine flows for heating air passing therethrough. The air intake unit, the cooler unit and the heater unit are aligned in a case and mounted on a front space of a passenger room of the vehicle. However, due to the aligned arrangement of these three units, the air conditioners of this type tend to have a longer and bulky construction and thus they are not suitable for small-sized motor vehicles.
In view of the above, one compact air conditioner has been proposed and put into practical use for such small-sized motor vehicles, which is disclosed in Japanese Patent First Provisional Publication 8-282248. The air conditioner has such a construction that the evaporator and the heater core are stood and arranged closely in a case and aligned longitudinally in a motor vehicle. For obtaining much compact construction, a measure is further employed wherein the cooler and heater units are integrated, by which the evaporator and heater core can be much closer to each other.
In operation, through the intake unit, air is led to the evaporator to be cooled and then distributed, by means of an air mix door, to upper and/or lower air flow passages, the lower air passage having the heater core installed therein. The air mix door is of a slide door type that slides up and down in front of mouth portions of the upper and lower air flow passages. Due to usage of this slide type door, the distance between the evaporator and the heater core can be shortened. The cooled air directed to the lower air passage is heated by the heater core and led to an air mix chamber where it is mixed with the cooled air that has passed through the upper air passage. Thus, the temperature of the air mixed in the air mix chamber depends on the work position of the air mix door. The mixed air thus having a certain temperature is then distributed to various portions of a passenger room through various air blowing openings formed in the case. Usually, mode doors are provided to the air blowing openings for providing the air conditioner with a plurality of air distribution modes.
For moving the slide type air mix door in the above-mentioned manner, a driving mechanism is employed which generally comprises a rack which is provided on the air mix door, a gear which is rotatably held by the air conditioner case and meshed with the rack and an electric actuator which drives the gear. Thus, when the electric actuator is energized for a given time, the gear is rotated by a certain angle and thus the air mix door is moved up or down to a desired work position.
However, even the above-mentioned compact air conditioner has the following drawback.
Due to its inherent construction, the air conditioner needs a troublesome and time-consumed assembling work. In fact, various parts, such as air mix door, gear, mode doors and the like should be installed in a limited space of the case. The case is of a split type including a front-half case for upstream air passsage and a rear-half case for downstream air passage. At the time of assembly, only the rear-half case is stood on a supporting jig with its open side facing upward, then the mode doors, air mix door and gear are put into the rear-half case from the open side to be set in predetermined positions, and then the upper-half case is put on the rear-half case to cover the open side of the same. Thus, position adjustment of the various parts should be done awkwardly in such a limited space of the rear-half case before putting the front-half case onto the rear. The position adjustment work becomes much severe when the positioning points needed by the parts increase. That is, the air conditioner of the publication needs a trouble some and time-consumed assembling work, which lowers the assembly work efficiency.
It is therefore an object of the present invention to provide an automotive air conditioner which can be assembled with easy assembling work.
It is another object of the present invention to provide an air conditioner which has a reduced manufacturing cost.
It is still another object of the present invention to provide an air conditioner which employs a slide type mixing door member.
It is a further object of the present invention to provide a measure for achieving the above-mentioned objectives.
It is a still further object of the present invention to provide an automotive air conditioner which generally comprises an upstream side case, a downstream side case and a mixing door assembly. The upstream side case defines therein an upstream air passage in which an evaporator is installed. The downstream side case has therein a first downstream passage which flows air heated by a heater core installed therein and a second downstream passage which bypasses the heater core. The airflow ratio between the first and second downstream passages is regulated by a slide type mixing door installed in the mixing door assembly. The mixing door is driven by an electric actuator through a sliding device. The mixing door assembly is detachably disposed between the upstream and downstream side cases.
According to a first aspect of the present invention, there is provided an automotive air conditioner, which comprises an upstream side case defining therein an upstream air passage; a downstream side case defining therein first and second downstream air passages which extend in parallel to an air mix chamber; an evaporator installed in the upstream air passage; a heater core installed in the first downstream air passage; and a mixing door assembly detachably disposed between the upstream and downstream side cases for varying the open degree of the first and second downstream air passages relative to the upstream air passage.
According to a second aspect of the present invention, there is provided an automotive air conditioner, which comprises an upstream side case defining therein an upstream air passage; a downstream side case defining therein first and second downstream air passages which extend in parallel to an air mix chamber defined in the downstream side case, respective mouth portions of the first and second downstream air passages facing a downstream end of the upstream air passage when the upstream and downstream side cases are coupled; an evaporator installed in the upstream air passage; a heater core installed in the first downstream air passage; and a mixing door assembly detachably disposed between the upstream and downstream side cases. The mixing door assembly includes a door housing and a slide type door member which is slidably installed in the door housing for varying an airflow rate between the first and second downstream passages.